Numeral wheel locking mechanism



Dec. 15, 1953 c. F. QEBB 2,662,690.

NUMERAL WHEEL LOCKING MECHANISM Original Filed Nov. 22, 1948 2Sheets-$heet 1 dti/ Q di/ 3 (6 m I v: Q) 8 LO 9 N 7 s y 0') (IS 1 s N r2" q R 5 Q. R, N N I m N .O s a N a INVENTOR. N a CHRISTOPHER FREDERICKWEBB Dec. 15, 1953 c, F WEBB NUMERAL WHEEL LOCKING MECHANISM 2Sheets-Sheet 2 Original Filed Nov. 22, 1948 CHRISTOPHER FRED ERICK WEBBPatented Dec. 15, 1953 UNITED STATES PATENT OFFICE assignor to BellPunch Company Limited, London, England, a British company Originalapplication November 22, 1948, Serial No. 61,348. Divided and thisapplication February 25, 1950, Serial No. 146,186

Claims priority, application Great Britain December 2, 1947 3 Claims.

This invention relates to calculating machines and has particularreference to the type of calculating machine in which the driving rackis normally out of engagement with the registering wheels, for examplethe type of machine disclosed in my United States Patents No. 2,291,853,dated August a, 1942, and No. 2,355,714, dated August 22, 1944, and inmy British Patent No. 522,721, accepted June 25, 1940.

In the type of machine just indicated there is provided a calculatingmachine in which the movement of a key is transmitted through a chain oflinks to a rack movable to transmit motion to a pinion operativelyconnected to a numeral wheel, one of the links of the said chain oflinks being connected to the rack so that any movement of the said linkrelatively to the rack is solely of a pivotal nature, and being operablethrough the remaining links of the chain to impart to the said rack,when moving toward or away from its initial position of rest, arelatively slow motion. In brief, the chain of links insures that as thequadrant rack moves from its position of rest it gradually increases itsvelocity and, when making its return stroke, moves back to its positionof rest gradually. In their final movement both the quadrant rack andthe pinion connected to the numeral wheel are brought to rest before thelinks of the chain have ceased moving. This arrangement insures thatupon the return of the quadrant rack to its initial position any suddenjar is completely eliminated.

The improvement provided in accordance with the present inventionrelates to the provision of means whereby the numeral wheels arenormally locked against rotation and which, when they are about to beset in motion as the result of actuation of a key, are automaticallyreleased from said lock.

Hitherto in calculating machines of the character indicated, a pinionwheel associated with the numeral wheel is arranged to engage with ayieldingly controlled pawl which, when the pinion is set in motion asthe result of actuation of a key, yields against the motion of thepinion so as to permit the same to rotate. It will be appreciated thatin such circumstances the pinion is not positively locked againstrotation, but is merely held in a predetermined position by a yieldinglycontrolled pawl engaging with the pinion between two of its teeth, butin such fashion that when the numeral wheel is moved the pawl will yieldto such movement. With a yieldingly controlled pawl it is necessary tohave a driving spring for the pinion of the numeral wheel much strongerthan would be the case if the numeral wheel was not controlled by ayieldingly controlled pawl. According to the present invention, sincethe pressure on the pinion is relieved, a lighter driving spring isrequired and, consequently, the operator need not exert such highpressures upon the keys as when a yieldingly controlled pawl is used.

In accordance with the present invention there is associated with eachpinion means normally locking the same positively against rotation andwhich, when a pinion is about to be set in motion as the result of theactuation of a key, automatically releases the pinion. Thus the frictioninherent in any type of yieldingly controlled pawl is completelyeliminated enabling a lighter touch of key operation to be employed.

The objects of the present invention relate to the attainment of theends above indicated. These general objects as well as objects relatingto details of construction and operation will become apparent from thefollowing description read in conjunction with the accompanyingdrawings, in which:

Figure 1 illustrates in vertical section the devices associated with onebank of keys of a machine of the type described; and

Figure 2 is a diagram particularly illustrating the actuation of therack controlling linkage above referred to.

As will be evident from reference to the prior patents mentioned above,the machine is of the general type disclosed therein and there are notherein detailed those elements of the complete machine which are knownto the art through the disclosure of said patents, the disclosure beingconfined to those devices which include the improvements embodying thepresent inventions.

The bank of keys 2 illustrated in Figure 1 have associated with them akey bar I, the movement of which is transmitted through a chain of links3, 4, 5, 6 and i to a quadrant rack 8 movable to transmit motion indegree related to the operated key to drive a pinion 9 connected to anumeral wheel IS. The link 1, of the said chain of links, is connectedto the quadrant rack 8 so that any relative movement between thequadrant rack 8 and the link i is solely of a pivotal nature. The link Iis operable through the remaining links of the chain to impart to thequadrant rack 8 a velocity which increases from zero. The returnmovement of the quadrant rack 8 to its position of rest is also effectedgradually thus insuring that the quadrant rack 8 is provided, both atthe commencement of its movement and at the end thereof, with arelatively slow motion which reduces the inertia of the quadrant rackand the numeral Wheel 9 to a minimum and assures the smooth and gradualarrest thereof.

When a key 2 is depressed an abutment thereo engages with the key bar lto move the same downwardly. The key bar I is connected at substantiallythe ends thereof to a bell crank lever H pivoted at lid on a fixedtransverse pin and to a link kl which is shaped as a bell crank lever.The construction is such that as a key is moved downwardly the key barmoves downwardly and inwardly as described in said patents. As the keybar moves downwardly it imparts through the pins of links 3 to l,inclusive, to the quadrant rack 8 a motion which will be morespecifically set out in describing Figure 2. It will be observed thatthe link 3 is pivotally connected to both the key bar and the link l bypivot pins i2 and E3. The link 4 is pivotally mounted upon a fixed pin lwhich extends the entire breadth of the machine, and is ccrmnonto thevarious key orders thereof. The end of the link 4, remote from thatwhich is connected to the link 3, is pivotally connected to the link 5which in turn is pivotally connected to a point intermediate the lengthof the link 5 which is shaped as a bell crank lever. The upper end ofthe link 5 is pivoted upon fixed spindle l6 which extends through theentire breadth of the machine. The lower end of the link 6 is pivotallyconnected to the link 1 which in turn is connected through a pivot pinto the quadrant rack 8 so that the only movement of the link irelatively to the quadrant rack 8 is a pivotal movement, therebyavoiding any sliding movement of the pivot in a cam groove as disclosedin Patent No. 2,356,714.

Referring specifically to Figure 2, there is dia grammaticallyillustrated the operation of the chain of links as the key 2a carryingthe numeral 9 is depressed to move the quadrant rack 8 from its positionof rest through its complete movement of nine teeth. An arm 4a of thelink 4 is shown pivotally connected at A: to a selector bar i'l. As thekey 2a of the series of keys 2 is operated it moves, through the mediumof the bell crank levers I i and 4, with selector bar ll through thepositions marked A, B, C, D and E.

As the selector bar is moved through these positions the pivot pin ofthe arm 6a moves through the positions A1, B1, C1, D1, and E1 and thefree end of the link 3, shown as pivotally connected atAz to the link 5moves through the positions A2, B2, C2, D2 and E2 while the end of thelink 5 which is shown as pivotally connected at A3 to the link 6 movesthrough the positions A3, B3, C3, D3 and E3. The movable end of the link6 is pivotally connected at A4 to the link I and moves through thepositions A4, B4, C4, D4 and E4 while the link l which is pivotallyconnected at A5 to the quadrant rack 3 does not move at all during theinitial movement of the other links from their A to their B positions,after which the end of the link i which is pivotally connected to thequadrant rack 5 takes up the successive positions 05, D5 and E5. Theinitial positions As and B5 are coincident. As the link 1 moves so thatthe quadrant rack 8 is moved the successive positions of the first toothare those indicated at A6, B6, C6, D5 and Es, As and B6 beingcoincident.

It will be observed that during the operation of the machine the upwardmovement of the rack may be arrested by the appropriate key at anystationary point about which the link 71' can swing to permit thequadrant rack 8, when released, to move into mesh with its pinion 9. Itshould further be noted that at any one of the said nine positions thelink i will insure that the tooth engagement of the quadrant rack 8 withthe pinion 9 is in a substantially radial direction relatively to thepinion 9.

It will be observed from the above that upon the initial movement of thekey the operator merely sets the chain of links which is to operate thequadrant rack 8 into motion, Without effecting any movement of the rack8 itself, after which the quadrant rack 8 is moved to an accelerateddegree. Referring to Figure 1 it will be observed that the main spring[8 is anchored to a lateral extension 41) of the link A, the arrangementbeing such that shortly after the movement of the link has commenced theanchorage point of the extension 4b of the link rises so as to cause theeifective leverage of the tension spring l8 about the pivot 15 todiminish as the tension of the spring [8 increases, The arrangement ofthe link l and extension db thereof is designed to produce asubstantially constant 'resistance to the pressure of the operatorsfinger throughout an operating stroke. As the connection between thelink I and the quadrant rack 8 is of a purely pivotal character,friction is minimized as contrasted with that involved in a sliding pinand slot.

Upon the completion of a key stroke the quadrant rack 8 is released bythe trip mechanism as hereinafter described and is moved under theinfluence of the driving spring [8 into engagement with the pinion 9,this being effected through the pivotal connection of the rack to thelever I9 to which the rear end of the spring is secured. As the quadrantrack returns to its position of rest under the influence of the springI8 and therefore returns the pinion 9 and the numeral wheel It to theirpositions of rest it arrives at such a position of rest before the chainof links forming the operative connection be tween the quadrant rack andthe key bar have ceased moving. Consequently, it is insured that thenumeral wheel 10 and its pinion 9 are stationary before the mechanismeffecting the Withdrawal of the rack from the pinion 9 is brought intooperation.

Associated with each pinion 9 there is a pawl 2| and locking lever 22.This arrangement normally locks the pinion 9 against rotation, and anarrangement is provided which, when a pinion 3 of a bank of keys isabout to be set in motionas the result of actuation of a key,automatically releases the pinion. The pinions 9 are released eitherwhen the rack 8 positively moves the pinion or when a transfer mechanism23 rotates through the medium of pins 23a a toothed wheel 24 connectedto the pinion 9. This transfer mechanism is disclosed in Patent No.2,291,853, and need not be described in detail except to the extent ofreference to the pins 23a.

First, dealing with the instance where the pinion 9 is moved by the rack8 it will be evident that when the trip mechanism described hereafterreleases the rack 8 the lever 22 is moved in a counterclockwisedirection about its pivot 21 by the flexing of a spring 28 connectedbetween it and the lever I9. One end of the leaf spring 28 is attachedto a horizontally extending portion of the upper end of the lever I9 bymeans of a nut and bolt arrangement [9a. Ihe other end of the leafspring 28 is provided with a forwardly turned portion 28a which passesthrough a bore in the right hand end of the lever 22 as viewed inFigure 1. By this flexing action the lever 22 is moved downwardly andout of engagement with the locking surface 29 with which it normallyengages. The pawl 21 released from its positive locking engagement withthe pinion 9 permits the numeral wheel to be freely rotated.

Due to the fact that the pawl 2% is not of a yieldingly controlled typewhich snaps into and out of engagement with the tooth of the pinion 9the operation of the numeral wheel is rendered less noisy than in thecase of a pinion wheel which is restrained by a yieldingly controlledpawl.

When a numeral wheel of a lower order is transferring to a numeral wheelof a higher order the pins 23a are arranged to engage with the righthand lateral extension 2212 of the locking lever 22 to swing the same ina clockwise direction about its pivot 21 so as to move the locking leverout of engagement with the locking surface of the pawl 21. After thetransfer action has taken place the pawl again becomes locked in theposition indicated, this being insured by contact of pin 23a with theleft hand extension 22a of the locking lever.

It has been shown that the numeral pinions are always positively lockedexcept when an adding or transferring operation is in progress, but itwill be appreciated that it is also necessary to remove any obstructionfrom the path of the pinions during a cancelling operation in order topermit the numeral wheels to be returned to zero. For this purpose theremay be provided means for displacing by manual operation of a cancellever all of the pawls 2| in the axial direction of the pinions 9 sothat the pawls 2| are temporarily moved out of the path of the pinions 9without in any way interfering with the looking functions alreadydescribed. A spring 2m has one end engaged in a bore in a horizontallyextending portion Zlb of the lower end of the pawl 2| and its other endin engagement with a fixed transverse pin Zlc. The spring Zla isarranged to exert a slight torque on the pawl 2! in an axial directionto return the tip of the pawl into the plane of the pinion following acancelling operation.

It will be seen that according to the present invention there isprovided a calculating machine in which the pinions of the numeralwheels are normally locked positively against rotation, and wherein thearrangement is such that when the pinion wheels are about to be set inmotion the positive lock is released and the pinion wheels are free tobe rotated eliminating all friction and enabling a lighter key touch tobe employed in view of the fact that the driving spring l8 need not beas strong as would be the case if a yieldingly controlled pawl wasemployed.

After the rack 8 has moved free of the pinion to the degree determinedby the key which has been operated, it must be permitted to engage thepinion and this action is effected upon full depression of the key. Thelower end of a key stem, when it reaches the position indicated indotted lines at 2?), is adjacent one of the projecting lugs 32 formed ona trip bar 33. When the key stem reaches the dotted position a tooth ofthe bar I! will have reached the face of the key at 2b and at the sametime, a groove 20 formed in the opposite face of the key will becoincident with the lower guide through which the key passes. When themoving bar I! touches the key the latter is therefore displacedhorizontally a small amount, whereby the lug 32 and the trip bar 33 aremoved from right to left as viewed in Figure 1. This movement of thetrip bar 33 swings catch lever 34 pivotally mounted at 35 about thismount so as to move the end 36 thereof out of engagement with a tongue31 carried by the lever 19 which at pivot point 3! is connected to therack 8. When the catch lever 34 is released from the tongue 3'! thespring 18 urges the rack in a direction toward the pinion 9 of thenumeral wheel 10.

It will be noted that the lever i9 is released by the roller 28 on thebar I"! when a key is depressed, and that this same roller effectsdisengagement of the rack 8 from the pinion 9 by its action on the leverid when a key is released to its uppermost position. When the lever i9has been released by the roller 26, the line of thrust of the spring 28connecting the upper end of the lever l9 with the right-hand end of thelever 22, as viewed in Figure l, is such as to urge the lever 22 torotate in a clockwise direction about the pivot 23'. This rotation isresisted by engagement of the extension 22a with the pin 23a. It is notuntil the end 35 of the latch lever releases the tongue 37 and permitsthe spring [8 to urge the lower end of the lever 19 to the right, asviewed in Figure 1, that the flexing of the spring 28 rotates lever 22counterclockwise about its pivot 21 and releases the pawl 2i.

Thus it will be seen that the movement of the bar ll of the mechanism,in response to the depression of a key, causes the release of catch 36without direct vertical contact of the end of the key stem as formerlyrequired, and in ordinary operation the trip is effected by the momentumof the mechanism without direct influence from the key. Such anarrangement practically eliminates that harshness introduced by the deadend stroke operation inherent in the arrangement described in saidBritish Patent No. 522,721.

This is a division of my application Serial No. 61,348, filed November22, 1948, now Patent No. 2, 569,508, and contains subject-matter commonwith my divisional application, Serial No. 146,187, filed February 25,1950.

What is claimed is:

1. In a calculating machine of the type referred to having a pluralityof orders, each order including a plurality of keys, a numeral wheel, apinion connected to said numeral wheel, means through which actuationsof said keys produce variable movements of said numeral wheel, means foreffecting transfer movements from the numeral wheel or" one order to anumeral wheel of next higher order, and means normally positivelylocking said numeral wheel against rotation, said last mentioned meansincluding a pawl normally held in non-yielding engagement with saidpinion, a locking surface formed on said pawl and a catch in engagementwith said locking surface preventing movement of said pawl, said catchcomprising a pivoted lever normally arranged in engagement with saidlocking surface formed on the pawl and movable in one direction aboutits pivot and out of engagement with the locking surface on the pawl bythe movement of said first mentioned means and movable in anotherdirection about its pivot and out of engagement with the locking surfaceon the pawl by the operation of the transfer means.

2. In a calculating machine of the type referred to havin a plurality ofkeys, a numeral wheel rotatably mounted on a fixed axis, a pinionconnected to said numeral wheel, means including a rack gear throughwhich actuations of said keys produce variable movements of said numeralwheel, said rack gear being normally disengaged from said pinion andbeing in engagement therewith during periods of movement of said pinion,and means normally positively looking said numeral wheel againstrotation, the last mentioned means including a pawl normally held innon-yielding engagement with said pinion, a locking surface formed onsaid pawl and a catch in engagement with said locking surface preventingmovement of said pawl, said catch comprising a pivoted lever, said firstmentioned means including means for moving said pivoted lever about itspivot to release said pawl during periods of engagement of said rackgear with said pinion.

3. In a calculating machine of the type referred to having a pluralityof orders, each order including a plurality of keys, a numeral wheel, apinion connected to said numeral wheel, means through which actuationsof said keys produce variable movements of said numeral wheel, means foreifecting transfer movements from the numeral of one order to a numeralwheel of next higher order, and means normally positively locking saidnumeral wheel against rotation, said last mentioned means including apawl normally held in non-yielding engagement with, said pinion, alocking surface on said pawl and a catch in engagement with said pawlpreventing movement of said pawl, said catch compris n a pivoted levernormally positioned to have a portion thereof in engagement with saidlockin surface formed on the pawl, said pivoted lever including a pairof arms extending from the pivoted lever on either side of its pivot,the pivoted lever being movable in one direction about its pivot and outof engagement with said pawl by the movement of said first mentionedmeans, and means including said pair of arms for moving said pivotedlever in the opposite direction about its pivot and out of engagementwith said pawl by operation of the transfer means and for moving saidpivoted lever in said one direction about its pivot and into engagementwith said pawl by continued operation of the transfer means.

CHRISTOPHER FREDERICK WEBB.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 371,496 Felt Oct. 11, 1887 1,510,951 Morse Oct. 7, 19242,308,940 Sundstrand Jan. 19, 1943

